PURPOSE: To compensate the temperature characteristic in an excellent way with simple constitution without increasing power consumption by using a magnetic circuit comprising a permanent magnet and a magnetic adjusting plate made of soft ferrite whose magnetic characteristic is respectively specific so as to apply a DC bias magnetic field.
CONSTITUTION: The magnetic circuit is formed by combining a permanent magnet whose remanence or average remanence at room temperature is a value or over expressed in equation I and whose linear temperature coefficient of the remanence or average remanence is a value or over expressed in equation II and the soft ferrite magnetic adjusting plate whose saturated magnetization or average saturated magnetization at room temperature is a value or over expressed in equation III and whose linear temperature coefficient at room temperature of them is a value or below expressed in equation IV. In applying a bias magnetic field to a microwave element utilizing the ferrimagnetic resonance in the magnetic circuit, a conditional equation is established, where the resonance frequency is a frequency f0 independently of temperature. Thus, excellent temperature compensation is applied without supplying external energy and increasing power consumption with simple constitution. In the equations above, f0 is operating frequency, γ is gyromagnetic ratio, NZY is anti-magnetism coefficient of YIG, and 4πMSOY, α1Y is first-order temperature coefficient of saturated magnetization of YIG.
TANAKA HIDEO
MIYAKE MASAMI
ITO SEIGO
TAMADA HITOSHI
YAMADA TOSHIRO
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